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Just another modeller
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**** Are you using DC or DCC David? To be honest 7/.02 is marginal on either really, but is definately far too small for DCC track bus wiring.

It is WAY too small for turnout motors - for that you need at the very least double the size, preferably larger (voltage drop will be an issue - a peco or seep point motor draws about 4 amps momentarily and over any length of that small wire, you will lose a lot of voltage)

Richard
 

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Just another modeller
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9,983 Posts
***Chris: Literal translations of linear impedance are not useful for what we do if long term reliability and best performance is the objective. I see myriad problems with underwired layouts, virtually none with those wired to good standards. Compromise has a cost.

(1) Modellers make imperfect wiring usually - and even when well done, each soldered joint is resistive. Using a linear calculation for wire voltage drop is useful for calculating circuit design such as coil impedances but not for model railways. There are too many other factors.
(2) For example if we use AC then the inductance of the two wires which complete the circuit greatly increases the linear impedance and voltage drop will be magnified many times. Drops of 15~25% would be reasonably expected with fine wire to an AC coil depending on how the wires are run on an average layout.
(3) The momentary current draw of a PL10 peco point motor is 4 amps minimum. If the switch sticks, then 7/.02 will literally burn off the insulation as it fails. We should be using wire which has at least double the maximum current expected for point motors - and that is very much larger than 7/.02
(4) If DCC is being considered at any stage, now or in the future, it would pay to wire more heavily....With DCC, 7/.02 is marginally OK for short droppers or low current devices like LEDs or detectors but not enough for any other part of the layout.

regards

Richard
 

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Just another modeller
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9,983 Posts
***Hi Pimkib

For the power bus 32/.2 is a good size - big enough for a small layout but not too hard to work with. For droppers, about half that weight would be ideal, but as long as they are shortish - ie less than 300mm, then 7/02 will be OK but its better to go a wee bit heavier if you can. DCC Wiring isn't complicated, just ask whatever you like and we'll help - or, if you like, send me by email (or post on list if you can post images) and it can be marked up for wiring for you.

Richard
 
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